Questions regarding Albert Einstein's theory that posits, among other things, the equivalence of mass and energy.

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3
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2answers
134 views

time on earth compared to completely stationary in space

I recently started trying to understand the theory of relativity and I have the following question. Because earth is orbiting the sun at approx 67,000 mph (and its my understanding time slows down ...
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1answer
59 views

How would Special relativity explain past-present-future if thinking about 13-billion-light-years distanced objects

Halo. I'm interested in how would Special relativity comment on this: Suppose there are 2 objects, A and B. They are 13 billion light years away from each other. When the light from the B object ...
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2answers
47 views

What happens if two galaxies collide very quickly?

What would happen if two galaxies collided very quickly (e.g. at near the speed of light)? Would they mostly just pass through eachother unscathed, or would there be very energetic collisions that ...
6
votes
2answers
258 views

Age of the universe and time dilation

Given our knowledge and the standard cosmological model, we estimate that the age of the universe is about 13.7 billion years old. How much sense does it make to talk about the age of the ...
0
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1answer
81 views

Thought experiment about the outskirts of the universe [closed]

Suppose I aim at some object that is 13 billion light years away from Earth. Let's assume I have a twin that pilots a ship that travels in infinite speed, meaning that he can reach that object and ...
2
votes
1answer
107 views

If an object with mass were to somehow go the speed of light, would it destroy the whole universe?

Would an object with mass traveling the speed of light destroy the whole universe because it would have infinite energy / mass? According to ...
3
votes
1answer
350 views

Would time go by infinitely fast when crossing the event horizon of a black hole?

If you were to fall into a black hole, my understanding is that from your reference point, time would speed up (looking out to the rest of the universe), approaching infinity when approaching the ...
0
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2answers
99 views

Length contraction of a star

Something moving toward or away from us will be contracted in length according to special relativity. As the M31 galaxy is moving toward us at great speed it's "depth" should appear slightly ...
3
votes
1answer
70 views

Did time pass more slowly in the past?

13 billion years ago, the universe was about 600 million years old according to many scientists. At that time, all matter in the universe would have to be closer, or in other words denser. Did time ...
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votes
3answers
195 views

Does gravity slow or speed light up?

The speed of light in a vacuum is presumably the fastest speed possible. if gravity bends the course of light, does this imply that gravity the retards light so it is moving at a slower speed? If ...